I have persistable java classes "eg.Story" and "eg.Author"

Author is a property of Story, as is LanguageCode

I wish to find all Stories by that Author

right now I am trying somthing along the lines of



but obviously that fails as the compiler wants me to provide a hibernate Type, not a class as I first guessed.

I have googled about for some examples but alas have come up dry. I keep seeing references to 'left joins' and suspect that may be what I am after, but like I say in my subject line, I am a sql dummy and have no idea what a 'left join' is.

can someone help me with this, or point me at some good docs where i can read up on HQL for SQL dummies?

also if I don't care about the language code for some queries then is is acceptable to set

and assume that it will function as a wildcard, or do i have to test for null and change my query accordingly?

dave

Use the Hibernate.entity() method...



Or even:


I manually check for nulls and build up appropriate HQL. The other option is to use your database specific wildcard character (on Oracle, for example, you'd have to change the = to LIKE and use % as the wildcard).

A left join is a type of "optional" or "outer" join. Thats probably not what you want here. Optional joins say to return rows in the joined result even if there is no match in the joined table. Here it would basically say to return a Story even if there was no Author associated. Outer joins are typically slower.

HTH